LOYOLA COLLEGE (AUTONOMOUS), CHENNAI – 600 034
B.Sc. DEGREE EXAMINATION – CHEMISTRY
THIRD SEMESTER – APRIL 2012
CH 3502 – ORGANIC FUNCTIONAL GROUPS – I
Date : 24-04-2012 Dept. No. Max. : 100 Marks
Time : 9:00 – 12:00
PART – A
Answer all the questions: (10 x 2 = 20 marks)
- Vinyl halides are less reactive towards nucleophilic substitution reaction. Why?
- Arrange the following bromides in the order of ease of dehydrohalogenation by alc. KOH.
- What happens when propanone reacts with CH3MgBr followed by hydrolysis?
- Convert aniline to phenol.
- Give the IUPAC names of the following ethers:
- What happens when anisole( methoxy benzene) is hydrolysed with HI? Write the reaction.
- Identify the compounds A and B:
H2/Pd, BaSO4 HCN
C6H5COCl ——————–→ A ——————–→ B.
- Two isomeric compounds A and B, with molecular formula C3H6O , form oxime with hydroxyl
amine. Tollens test is answered by compound B only and iodoform test is answered by compound
A only. Give the structures of A and B and state reason.
- What is trans-esterification reaction.
- Why is α-chloroacetic acid more acidic than chloroacetic acid ?
SECTION – B
Answer any eight questions: (8 X 5 = 40 marks)
- Explain the reactions involved in the free radical chlorination of methane.
- Predict the major product of the following reaction and explain.
(CH3)3 C CH= CH2 + HBr ————→ ?
- Explain Reimer-Tiemann reaction.
- Convert phenol to : i). benzaldehyde, ii) benzoic acid. (2.5 + 2.5)
- Describe the mechanism of hydroboration-oxidation of propene to 1-propanol.
- What happens when tert-butyl methyl ether is hydrolysed using HI? Explain.
- Write the mechanism of acid catalysed ring opening of ethylene oxide.
- Explain Wittig reaction with a suitable example. Bring out the advantage of this reaction.
- What are the products formed when acetophenone reacts with each of the following compounds?
Write the reactions.
- i) LiAlH4 in THF followed by hydrolysis , ii) HCN. (2 x 2.5)
- Write a short note on Norrish type I reactions.
- Differentiate between maleic and fumaric acids.
- Write a brief account on the action of heat on α, β hydroxy acids.
SECTION – C
Answer any four questions: (4 X 10= 40 marks)
- a) Describe E1 mechanism with an example.
- b) 2, 4 –dinitro chloro benzene undergoes nucleophilic substitution much faster than Explain your answer.
- a) Explain Kolbe’s reaction with mechanism.
- b) Carry out the following conversions:
- i) (CH3)2 CH CH2OH ——–→ (CH3)3COH
- ii) (CH3)3CBr ——————-→ (CH3)2 CH CH2 (2.5 + 2.5)
- a) Describe alkoxymercuration and demercuration procedure for the synthesis of ethers
with an example.
- b) How are the following compounds prepared from ethylene oxide?
- i) butan-1-ol ii) 2-methoxy ethanol. (2+3)
- Write a short note on :
- a) Michael reaction b) Perkin’s reaction (5+5)
- Provide any one method to prepare the following compounds.
- i) succinic acid ii) cinnamic acid iii) crotonic acid iv) phenyl acetate
- v) phthalic anhydride (5 x 2)
- Compound A with molecular formula C7H6O on treatment with con.NaOH gives compounds B and
- B on oxidation gives back A. A answers Tollens test but not Fehing’s test. Compound C on
acidification gives D (C7H6O2). D gives brisk effervescence with aqueous NaHCO3 and reaction with
ethanol in the presence of dil.H2SO4 gives a sweet smelling compound E. Identify A, B, C, D and E
and write the reactions involved. Write all possible isomers of A.
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